以下是引用荆棘鸟在2004-5-20 5:40:00的发言:
QM试卷上的题目:explain what is meant by saying that these three variables are cointegrated and what is the statistical importance of cointegration. 这怎么答?
简要回答:
if the three variables are integrated (i,e Non-stationary) respectively, say, I(1), and if some combination of the three varibales is stationary(i,e, I(0) ), then we say the three varibale are cointegrated.
the statistical importance of cointegrationm is straightforward: if a variable is stationary, it is easy to handle with in terms of statistical inference,such as mean, variance, covariance and of course hypothesis testing.
例如:
宏观经济数据中(quarterly data, say), 消费和收入通常都是n##被过滤##tationary的,因此不便于我们研究。但注意到它们的一种线性组合:收入-消费=储蓄则是平稳过程。这时我们说消费和收入是cointegrated.
上面只是一个大意描述。
什么,你不知道什么叫stationary? 这这这........ |